Not unless your house is right next to hers and you broadcast a wireless signal.

In the past, some cable connections would come with a free dial-up connection for travel. Some of them did; I doubt they do now. That would be your other option if you are grandfathered into such a program - giving her that info to use. Gosh that's slow though.

Just get her a cheap DSL line if it's important to get her onto the internet.